Aircraft display with potential thrust indicator

ABSTRACT

An aircraft display apparatus combines a flight path vector group with a potential thrust indicator. The display apparatus comprises a display screen and a pitch ladder symbol, a horizontal line and a flight path vector group displayed on the display screen. The flight path vector group comprises a flight path vector symbol, a potential flight path vector symbol, and a potential thrust symbol. The potential thrust symbol further comprises a thrust and drag limit symbol and at least one throttle symbol. The flight path vector group is oriented on the display screen in relation to the pitch ladder and the horizontal line. The position of the potential thrust symbol relative to the pitch ladder, flight path vector symbol and the potential flight path vector symbol represents current engine power and power limits of the aircraft.

FIELD OF THE INVENTION

The present invention relates generally to electronic displays foraircraft and more specifically to potential thrust indicator symbologyin an aircraft cockpit display for displaying aircraft engine thrust (orengine power) in terms of actual and potential aircraft flight path.

BACKGROUND OF THE INVENTION

Experienced aircraft pilots are familiar with aircraft handlingqualities under normal flight conditions. Thrust, weight, lift, and dragare the forces that act upon an aircraft. Maneuvering is accomplished byvariations of these forces and is controlled by the throttles and flightcontrols. The power produced by the engines determines the angle that anaircraft can fly and still maintain airspeed (e.g. neither acceleratenor decelerate). Similarly, the drag on the airplane determines thedescent angle that the airplane can fly and not accelerate. Aircraftdrag and engine thrust models are used to indicate engine thrust as aclimb or descent angle on the display where the greatest climb and thegreatest descent angle represents the maximum and minimum powerparameters.

Electronic displays such as Primary Flight Displays (PFD's), Head-UpDisplays (HUD's), Head-Down Displays (HDD's) and the like are well knownand widely used to display information in aircraft. FIG. 1 illustrates aconventional flight path vector group 10 presented to an aircraft piloton an attitude display. The display shows a horizontal line 50, whichindicates the axis of flight parallel to the horizon. Pitch ladder 60indicates the pitch or potential pitch of the plane. A flight pathvector (FPV) indicator 20 represents the sum of all forces acting on theaircraft and indicates the direction of aircraft translation throughspace. A speed error indicator 30 emanates from the FPV indicator 20 andrepresents the difference between the selected airspeed and the currentairspeed. The potential flight path vector (PFPV) indicator 40 isdisplayed in reference to the FPV indicator 20. PFPV indicator 40 is anindication of the aircraft's instantaneous acceleration along the flightpath. The angle at which the PFPV indicator 40 is displayed relative tothe pitch ladder represents the acceleration scaled by the accelerationdue to gravity. The FPV indicator 20 and the PFPV indicator 40 may beobtained from onboard inertial reference systems, Global PositioningSystem (GPS) aided attitude sensors, or the like. In FIG. 1, the displayindicates that the aircraft is accelerating (the PFPV indicator 40 isabove FPV indicator 20). Further, PFPV indicator 40 indicates that theflight path may be increased to approximately a 6-degree climb with noacceleration along the flight path.

However, with the prior art displays as described above, the pilot isgiven no direct indication of thrust. Rather, the pilot must utilizesome internal model (usually gained through experience) based on theexisting engine displays. Thus, there exists a need for an aircraftdisplay which not only provides the pilot with a means for directlysetting engine power to achieve desired performance, but also enablesprecise aircraft speed control with a reduction in pilot workload andprovides control symbology in the pilot's primary field of view.

SUMMARY OF THE DISCLOSURE

Various aspects of the present invention provide an aircraft displayapparatus which combines a flight path vector group with a potentialthrust indicator to reduce pilot workload. The display apparatusincludes a display screen, a pitch ladder symbol displayed on thescreen, a horizontal line (representing level flight) displayed on thescreen and a flight path vector group displayed on the screen. Theflight path vector group includes a flight path vector symbol, apotential flight path vector symbol, a potential thrust symbol, and aspeed error indicator. The flight path vector group is oriented on thedisplay screen in relation to the pitch ladder and the horizontal line.The position of the potential thrust symbol is relative to the pitchladder and represents current engine power and power limits of theaircraft.

In accordance with another embodiment of the present invention, thepotential thrust symbol further comprises a thrust and drag limit symboland at least one throttle symbol.

In accordance with yet another embodiment of the present invention, thepotential thrust symbol indicates the aircraft's climb capability with afailed engine.

In accordance with a further embodiment of the present invention, thepotential thrust symbol indicates the potential aircraft descent anglewhen drag devices such as speed brakes, flaps and landing gear areactivated.

These and other aspects of the present invention are described in thefollowing description, attached drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

A detailed description of embodiments of the invention will be made withreference to the accompanying drawings, wherein like numerals designatecorresponding parts in the several figures, and wherein:

FIG. 1 illustrates the display format of a flight path vector groupwithout the present invention.

FIG. 2 illustrates a display format of the present invention.

FIG. 3 illustrates forces that act on an aircraft in flight.

FIGS. 4A-E illustrates displays of the present invention in fivedifferent operational situations.

FIG. 5 illustrates a display format of the present invention indicatingfailure of an engine.

FIG. 6 illustrates a display format of the potential thrust indicator ofthe present invention with drag device symbology.

FIG. 7 illustrates components of an embodiment of the present invention.

FIG. 8 illustrates the invention embodied in an aircraft.

DETAILED DESCRIPTION OF THE INVENTION

The following descriptions are of exemplary embodiments only, and arenot intended to limit the scope, applicability or configuration of theinvention in any way. Rather, the following description provides aconvenient illustration for implementing exemplary embodiments of theinvention. Various changes to the described embodiments may be made inthe function and arrangement of the elements described without departingfrom the scope of the invention as set forth in the appended claims.

Referring now to FIG. 2, a display of an exemplary embodiment of thepresent invention suitably includes a flight path vector group 100 whichincludes a FPV indicator 110, a speed error indicator 120, and a PFPVindicator 130. In addition, flight path vector group 100 of the presentinvention comprises a potential thrust indicator 160. Potential thrustindicator 160 provides the pilot with a means for setting engine powerto achieve a desired aircraft flight path and acceleration. Potentialthrust indicator 160 further includes thrust/drag limit indicators 170and first and second throttle indicators 180 and 190. FIG. 2 furthershows a pitch ladder 140, which corresponds to the pitch of theaircraft, and a horizontal line 150, which corresponds to the axis offlight parallel to the horizon. The entire flight path vector groupmoves with respect to pitch ladder 140. The numeric values associatedwith the above symbology elements of the flight path vector group may bedetermined from inertial data or other GPS aided attitude sensors.

As in the prior art, the FPV indicator 110 represents where the aircraftis moving through space. The PFPV indicator 130 represents the anglethat the aircraft may climb or descend while maintaining currentairspeed, e.g., the pilot may “fly” the FPV indicator 110 to the PFPVindicator 130 changing the aircraft's path through space whilemaintaining airspeed. However, using the potential thrust indicator 160in relation to the flight path vector group display, a pilot now maydirectly move the throttles to set engine power to achieve a desiredPFPV indicator setting. As described below, the PFPV is an expression ofthe aircraft's longitudinal acceleration scaled by the acceleration dueto gravity (≈32.1 feet/sec*sec). Advancing the throttles while keepingall else constant will add energy to the airplane and cause it toaccelerate. The pilot controls this acceleration referencing the changesin the placement of the PFPV. The power produced by the enginesdetermines the angle that the aircraft may fly and still maintainairspeed (e.g., neither accelerate nor decelerate). Similarly, the dragon the airplane determines the descent angle that the airplane may flyand not accelerate. The thrust/drag limit indicators 170 indicate to thepilot the maximum climb angle achievable at maximum power withoutacceleration and the maximum descent angle possible at maximum dragwithout acceleration. The throttle indicators 180 and 190 display theengine thrust contribution to the inertial indications.

The potential thrust available to an aircraft may be represented by amathematical equation. Referring now to FIG. 3, the forces acting on anaircraft in flight include thrust, lift, drag and weight. The currentpower of the aircraft engines and current vertical speed determines thepotential flight path angle Ø_(PFPA). A flight path angle Ø_(FPV) is thedirection of flight with respect to the earth. The “specific excesspower,” P_(S) (e.g., the excess power per unit weight), available fromthe engines is calculated using the following equation:

P _(S) =TV−DV/W=dh/dt+V/g dV/dt  (1)

where T is the thrust, V is the velocity, D is drag, W is weight, g isgravity, dh/dt is the climb rate, dv/dt is the acceleration of theaircraft and flight is at one “g.” By dividing the equation by V, theequation becomes one of “excess thrust” per unit weight and has no unitsof dimension:

T−D/W=1/V dh/dt+1/g dV/dt  (2)

The term on the left represents the net power being applied to theaircraft by the engines minus the drag. The position of throttleindicators 180 and 190 is scaled to this value by an air data computer.The maximum position of thrust/drag limit indicator 170 may bedetermined by the value of this term when throttles are at a maximum anddrag is at a minimum. The minimum position of thrust/drag limitindicator 170 may be determined by the value of the same term when dragis at a maximum and thrust is at a minimum. As is evident from thisequation, when a pilot wishes to maintain current aircraft speed, dv/dtis zero. Consequently, an increase in thrust will result in aircraftclimb. Similarly, when a pilot wishes to maintain current altitude,dh/dt is zero. Accordingly, any increase in thrust will result inacceleration.

Referring again to FIG. 3, each term in Equation 2 can be expressed asan angle:

Ø_(TA)=Ø_(FPA)+Ø_(PFPA)

where Ø_(TA) is the excess thrust angle, Ø_(FPA) is the flight pathangle and Ø_(PFPA) is the potential flight path angle. Modifications tothe excess thrust calculation may be applied to account for flight inother than one “g” situations.

FIGS. 4A-4E illustrates the displays of exemplary embodiments for fivedifferent operational situations. In FIG. 4A, the pilot has selectedmaximum power, as is evident by the fact that throttle indicators 180and 190 and PFPV indicator 130 are at the maximum thrust/drag limitindicator 170. In FIG. 4B, the pilot has selected a power setting lessthan maximum and the aircraft is accelerating (PFPV indicator 130 isabove FPV indicator 110). In FIG. 4C, the throttles are split (i.e., notat the same power setting) and below maximum power and the aircraft isaccelerating. In FIG. 4D, the power is set below maximum power and theaircraft is decelerating. In FIG. 4E, the power is set near maximumpower and the aircraft is maintaining current airspeed.

The present invention may also inform the pilot of available power whenan engine has failed. By way of example, FIG. 5 shows a potential thrustindicator 160 with throttle indicator 190 represented by an “x”,indicating that the right engine has failed. The left engine is at fullpower. By using potential thrust indicator 160, the pilot may determinethe aircraft's climb capability with a failed engine.

FIG. 6 shows a further optional embodiment of potential thrust indicator160 of the present invention with symbology representing performanceeffects of drag devices. Ø_(TAmax) represents the power available whenthrust is at a maximum, Ø_(DAmax) represents the power available whendrag is at a maximum and throttle indicators 180 and 190 are shown atidle. When the pilot extends the aircraft speed brakes, a speed brakeindicator 200 appears on the display. Speed brakes indicator 200represents the descent angle possible with speed brakes of the aircraftextended. When the pilot extends aircraft wing flaps, a flaps indicator210 appears on the display. Flaps indicator 210 represents the descentangle possible with the aircraft flaps extended. While FIG. 5 shows thedescent angle possible with flaps one (F1) extended, it will berecognized that a plurality of flap indicators may be shown (e.g., F2,F3, . . . ) relative to the number of flaps on an aircraft. When thepilot extends the aircraft landing gear, a landing gear indicator 220may appear on the display landing gear indicator 220 represents thedescent angle possible with the aircraft's landing gear extended.

FIG. 7 illustrates the components of an exemplary embodiment. Theembodiment is implemented on a head-up display (HUD). HUD 230 includes acombiner 230A, an overhead unit 230B, and a display computer 230C.Display computer 230C communicates display data to overhead unit 230Bwhich projects the display onto a display screen 230D of combiner 230A.The technology of these components is well known in the art and need notbe described in further detail.

The invention is not limited to HUD's and may be implemented on any typeof display including, but not limit to, CRT's, LCD's and HMD's(helmet-mounted displays). These displays are generically referred to aselectronic displays and are interchangeable with HUD 230 for thepurposes of the invention.

Electronic display (or HUD) 230 may obtain information from manyaircraft systems depending on the specific implementation. Theseaircraft systems may include display controllers 231, air data computers(ADC) 232, inertial reference systems (IRS) 233, performance computers234, flight guidance computers 235, flight management computers 236, andthe like.

In an exemplary embodiment as shown in FIG. 7, various components maycommunicate information to electronic display 230. For example, adisplay controller 231 communicates commands (e.g., on/off, mode,brightness, etc.) to electronic display 230. An air data computer 232communicates airspeeds, mach numbers, altitudes, vertical speeds, andthe like. An inertial reference system 233 communicates accelerationdata, attitude data, heading and position data, etc. A performancecomputer 234 communicates optimal flight path and cost information. Aflight guidance computer 235 communicates guidance parameters. A flightmanagement computer 236 communicates information including flight pathinformation and waypoints. Of course, other embodiments may includevarious other components.

FIG. 8 illustrates the invention embodied in an aircraft. An aircraft240 includes a frame 240A, engines 240B, a cockpit 240C and electronicdisplay 230 (shown external to the aircraft 240).

Thus, an aircraft display with a potential thrust indicator according tovarious aspects of the present invention provides an engine display thatis physically located in the pilot's instrument scan area (on theattitude display or HUD, for example). Further, the aircraft displaywith potential thrust indicator provides to the pilot a means todetermine engine power and engine throttle to set climb or descentangles of the aircraft. The aircraft display includes numerous otherfeatures and advantages that are not specifically identified herein.While the present invention has been described with reference tospecific preferred embodiments thereof, various changes may be madewithout departing from the scope of the invention as claimed. Inaddition, many modifications may be made to adapt the presentembodiments to a given situation without departing from it essentialteachings.

I claim:
 1. A display apparatus for an aircraft comprising; a displayscreen; a pitch ladder symbol displayed on said screen and representingthe pitch of said aircraft; a horizontal line displayed on said screenand representing the axis of flight parallel to a horizon; and a flightpath vector group further comprising: a flight path vector symboldisplayed on said screen; a potential flight path vector symboldisplayed on said screen; and a potential thrust symbol displayed onsaid screen wherein the position of said potential thrust symbolrelative to said pitch ladder symbol, said flight path vector symbol andsaid potential flight path vector symbol represents current engine powerand power limits of said aircraft.
 2. The display apparatus according toclaim 1 wherein said flight path vector group is oriented on saiddisplay screen in relation to said pitch ladder symbol and saidhorizontal line.
 3. A display apparatus according to claim 1 whereinsaid potential thrust symbol further comprises a thrust and drag limitsymbol and at least one throttle symbol.
 4. A display apparatusaccording to claim 3 wherein said aircraft has at least one engine andthe number of throttle symbols corresponds to the number of saidengines.
 5. A display apparatus according to claim 1 wherein saidpotential thrust symbol further comprises symbology representing enginepower and power limits of said aircraft with at least one drag deviceactivated.
 6. A display apparatus according to claim 5 wherein said dragdevice comprises a speed brake.
 7. A display apparatus according toclaim 5 wherein said drag device comprises at least one wing flapposition.
 8. A display apparatus according to claim 5 wherein said dragdevice comprises landing gear.
 9. A display apparatus according to claim1 wherein said display apparatus comprises a head-up display.
 10. Asystem for displaying engine power of an aircraft having a flight datacontroller, a display apparatus, and a display controller fortransmitting flight data from said flight data controller to saiddisplay apparatus, wherein said display apparatus comprises: a displayscreen; a pitch ladder symbol displayed on said screen and representingthe pitch of said aircraft; a horizontal line displayed on said screenand representing the axis of flight parallel to a horizon; and a flightpath vector group further comprising: a flight path vector symboldisplayed on said screen; a potential flight path vector symboldisplayed on said screen; and a potential thrust symbol displayed onsaid screen wherein the position of said potential thrust symbolrelative to said pitch ladder, said flight path vector symbol and saidpotential flight path vector symbol represents current engine power andpower limits of said aircraft, wherein said flight path vector group isoriented on said display screen in relation to said pitch ladder andsaid horizontal line.
 11. A system according to claim 10 wherein saidpotential thrust symbol further comprises a thrust and drag limit symboland at least one throttle symbol.
 12. A system according to claim 11wherein said aircraft has at least one engine and the number of throttlesymbols corresponds to the number of said engines.
 13. A systemaccording to claim 10 wherein said potential thrust symbol furthercomprises symbology representing engine power and power limits of saidaircraft with a least one drag device activated.
 14. A system accordingto claim 13 wherein said drag device comprises a speed brake.
 15. Asystem according to claim 13 wherein said drag device comprises at leastone wing flap position.
 16. A system according to claim 13 wherein saiddrag device comprises landing gear.
 17. A system according to claim 10wherein said display apparatus comprises a head-up display.
 18. A methodfor displaying flight data information to an aircraft electronic displayoperator comprising the following steps: obtaining flight datainformation; manipulating said flight data information; presenting saidflight data information on a display, wherein said display comprises: adisplay screen; a pitch ladder symbol displayed on said screen andrepresenting the pitch of an aircraft; a horizontal line displayed onsaid screen and representing the axis of flight parallel to a horizon;and a flight path vector group further comprising: a flight path vectorsymbol displayed on said screen; a potential flight path vector symboldisplayed on said screen; a potential thrust symbol displayed on saidscreen wherein the position of said potential thrust symbol relative tosaid pitch ladder, said flight path vector symbol and said potentialflight path vector symbol represents current engine power and powerlimits of said aircraft.
 19. The method of claim 18 wherein said step ofpresenting further comprises presenting said flight data information ona display wherein said flight path vector group is oriented on saiddisplay screen in relation to said pitch ladder and said horizontalline.
 20. The method of claim 19 wherein said step of presenting furthercomprises presenting said flight data information on a display whereinsaid potential thrust symbol further comprises a thrust and a drag limitsymbol and at least one throttle symbol.